Roll type continuous casting apparatus



June 3, 1969 E. A. OLSSON 3,447,590

ROLL TYPE CONTINUOUS CASTING APPARATUS Original Filed July 23, 1955Sheet of 2 I5 [6 b E INVEIBTOR.

Erlk Allan lsscm. F 1g. 5 BY 6 F'ig.E.

Attorneys.

June 3, 1969 o sso 3,447,590

ROLL TYPE CONTINUOUS CASTING APPARATUS Original Filed July 25, 1965Sheet 2 or 2 INVENTOR.

Erik Allan Olsso 72.

BY yvwwa, a., 1 ya,

Attorneys.

United States Patent Int. c1. B2211 11/06 US. Cl. 164277 7 ClaimsABSTRACT OF THE DISCLOSURE This application relates to apparatus forcontinuous casting of metal by flowing the molten metal into a reservoirformed between the surfaces of two or more revolving rolls that turntoward each other. The molten metal, congealing on the surface of therolls, is carried into a space between two rolls and emerges as a formedslab or strip. When the rolls are horizontal, there are end members atopposite ends of the rolls and cooperating with the roll surfaces toconfine the molten metal, and when the rolls are vertical there is anend member only at the bottom. This application discloses tapering orsloping the surface of each end wall member that is contacted by themolten metal away from the path of flow of the metal so that the metalcongealing on the surface of the rolls is continuously carried away andcannot become wedged under the end wall members.

This is a division of application Ser. No. 474,407, filed July 23, 1965,now abandoned, for Method of Manufacturing Products Directly From aMelt.

This invention relates to the continuous casting of metal by the use ofat least two oppositely-rotating rolls in sideby-side relation, usuallywith their axes horizontal, and with a space between the rolls throughwhich-formed metal emerges while molten metal is retained in a sumpformed above and between the rolls, with fixed end walls to retain themolten metal from escape at the ends of the rolls.

Apparatus of the type to which this invention relates is well known, buta difliculty with such apparatus has arisen from the construction of themetal-retaining end walls. In the operation of the rolls, the metalcongeals against the surface of the rolls and is carried by the rotationof the rolls toward a space between the rolls from which the formed slabor strip emerges. The metal layers so congealed form the oppositesurfaces of the slab or strip emerging below the rolls. Since the endWalls forming the ends of the sump must have a working clearance withthe rolls, congealed metal forms or works into the clearance between theroll and the end walls in the form of a thin fin or flash that becomeswedged between the end wall and roll to cause binding and galling thatimpedes the operation, disrupts formation of the edges of the emergingcasting, and even destruction of the roll surface.

The present invention is for an improvement in apparatus of this typewherein the end wall or walls are so arranged in relation to the moltenmetal that metal is constantly carried away from the surface of the endwall and thereby prevents packing or jamming of the metal between theroll surface and the end wall. This is accomplished by so forming thesurface of the end walls that they diverge away from the straight linedirection in which the congealed metal is carried by the rotation of therolls, so that as the molten metal flows against the face of the sidewall where it confronts the roll surface and congeals, it is constantlypulled away from the clearance space between the end wall and the rollsurface, and

the thin fin which has heretofore caused the trouble has no opportunityto form and become lodged under the end wall.

The invention is applicable not merely to an arrangement where there areonly two horizontal rolls between which the formed metal passes, but toarrangements where there is a cluster of rolls arranged to form twoslabs or strips moving in opposite directions, or where the rolls arevertical, in which case only one end wall at the bottom is needed.

In the drawings, which are largely schematic,

FIG. 1 is an end view of a casting apparatus embodying the invention;

FIG. 2 is a plan view of the apparatus shown in FIG. 1;

FIG. 3 is a fragmentary view of a larger scale showing a top plan viewof the two rolls of FIG. 1 and the end wall structure;

FIG. 4 is a schematic section through a casting apparatus having acluster of four rolls with two outlet passes for the simultaneouscasting of two strips or slabs;

FIG. 5 is a fragmentary top plan view of one end of the cluster of rollsshown in FIG. 4;

FIG. 6 is a perspective view showing the end wall construction of FIGS.4 and 5, apart from the rolls;

FIG. 7 is a top plan view, with the bearings removed, of a castingapparatus in which the axes of the rolls are vertical, and in whichthere is a cluster of four rolls also arranged to form two castingssimultaneously; and

FIG. 8 is a fragmentary view in vertical section in the plane of lineVIII-VIII of FIG. 7 showing the lower end of the apparatus of FIG. 7.

Referring first to FIGS. 1 to 3 of the drawings, it shows the generalarrangement heretofore proposed of two horizontally-disposed rolls 1side-by-side and spaced from each other as indicated at 5 to form a passthrough which the formed slab or strip emerges. The space above andbetween the upper surfaces of the rolls provides a sump or reservoir formolten metal 2, and the metal is retained from escaping at the ends ofthe rolls by upright end walls 3 near opposite ends of the rolls 1 andcontoured in the usual manner to conform to the surface of the rolls. Atundish arrangement for supplying molten metal to the reservoir inindicated at 2*. Various ways of supporting and holding the end walls inposition are known in the art and have not been shown, but onearrangement adaptable to this invention is disclosed in US. Patent2,128,941, granted Sept. 6-, 1938.

In the arrangement shown, the roll shafts 8 are supported in bearings 6which are pressure-sensitive electrical transducers. The shafts 8 aregeared together, as indicated by the gear box 7, for rotating the rollsin opposite directions so that their upper surfaces are moving towardthe gap 5, as indicated by the arrows in FIG. 1. There is a variablespeed drive or transmission 9 through which rotation of the motor 10 isimparted to the rolls, and the speed is controlled by an electricalcontrol 11 responsive to the pressure of the roll shafts in the hearing6, the schematic wiring 12 indicating such control arrangement.

As is usual in apparatus of this type, the rolls are watercooled, eitherby circulating water through them, or applying a water spray to thesurface. For simplicity of illustration, this has been indicated bywater sprays 13 in FIG. 2.

So much of the apparatus as has heretofore been described is generallyknown, except for the construction of the end walls 3. As most clearlyseen in FIG. 3, those surfaces 3 of the end walls which are contacted bythe molten metal, diverge from a plane transverse to the axes ofrotation of the rolls toward the central area 2 of the end 'Walls. Tostate it differently, the surfaces 2 slope away from the straight linedirection in which congealed metal on the surface of the rolls iscarried around the surface of the rolls toward the gap 5. These surfacesare smooth and free of any projection to which the metal will congeal orotherwise be restrained from being freely pulled away from them as themetal congeals and moves toward the pass between the rolls.

Looking at FIG. 3, if the rolls were stationary, the hydrostaticpressure of the molten metal would tend to force a thin film of metalinto the crevice between the roll confronting edges of the end walls andthe rolls, and if the end wall faces were in a plane parallel with thestraight line travel of the metal on the roll surface, such thin filmwould immediately congeal and form a wedge. The same would be true ifthe rolls were turning and the end walls were in such a parallel plane.However, with the end walls diverging from the straight line travel ofthe metal, or diverging in the direction of rotation of the rolls from atransverse plane through the rolls, the congealing metal is continuouslycarried away from the crevice. The curved portions of the flow arrows inFIG. 3 represent the molten metal flowing down and laterally against theend walls, and the straight portions of the arrows indicate the flow ofcongealed or congealing metal away from the crevice.

The remaining figures of the drawings indicate variations in the rollarrangement with a confining or end wall similarly angled away from adirection parallel with the straight line flow of the metal.

In FIGS. 4, 5 and 6, there is disclosed the adaptation of the inventionto a casting apparatus comprising a cluster of four rolls; the upper twodesignated 14 are spaced from each other and spaced to a lesser extentfrom the lower two, designated 15, and the two rolls 15 are in contactwith each other. Driving means, not shown, but which may be generallysimilar to that shown in FIG. 2, rotates each of the twodiagonally-opposed rolls in the same direction and opposite the othertwo, as indicated by the arrows. There are opposed end walls 16. Thearrangement provides oppositely-extending forming passes or gaps 17 forthe simultaneous formation of opposite laterallymoving strips or slabs18. To this end the confronting surfaces of the upper two rolls revolvetoward each other, and the confronting contacting surfaces of the lowertwo rolls turn opposite each other.

The end walls 16 in this arrangement are in metalconfining relation withthe top two rolls through an arc of nearly 180 and the walls adjacentthe rolls diverge in the manner heretofore described with reference tothe fiow of metal. The end wall structure so formed continuouslydecreases in thickness in the roll-conforming areas from the top throughthe extensions 16 that extend into and terminate in the metal-formingpasses at each side, and then increases in thickness downwardly in thearea 16 that fits into the space between the two lower rolls. Thischange of thickness occurs because of the formation of themetal-retaining surface of the end wall. The shape of the outer face isunimportant, but for simplicity of description, is here shown as beingplanar, in contrast to the compound slope of the inner face.

Referring now to FIGS. 7 and 8, there is also shown a cluster of rollsarranged in two pairs, those of one pair being designated 20, and thoseof the other pair 21. These rolls, however, have vertical axes, and thetwo pairs are spaced from each other to form two gaps or outlets 22 forthe formed castings, these being opposite each other. The rolls of eachpair contact each other, and as in previous arrangements, all rollsrotate at the same speed with the rolls of each pair being driven in adirection opposite the direction of the other roll of each pair, asindicated by the arrows. Also rolls between which the forming opening isprovided rotate, as in FIG. 4, in 0pposite directions. Thus the surfacesof left-hand rolls 20 and 21 have their confronting surfaces moving in adirection to force metal out between them, and similarly the confrontingsurfaces of the right two rolls move in a direction to move metal outthe gap at the right.

This arrangement requires an end plate 23 only at the lower end of theroll cluster, since the metal is poured into the central cavity 24 atthe top, and the formed strips or slabs emerge in a vertical plane. Thetop face of this end plate slopes in opposite directions from the centeroutwardly and downwardly in opposite directions, so that here, as in thepreceding apparatus, the end plate has surfaces which diverge from thedirection of straight-line flow of the metal, or which diverge from thecentral area outwardly relative to a plane passing transversely throughthe rolls. This is best seen in FIG. 8 where the surfaces 23 contouredto fit about the rolls slope in the abovedescribed direction andterminate in the metal-forming passes 22 In all embodiments heredescribed, the end wall or end walls which contact the metal are smoothand free of any obstruction or irregularity that would impede the flowof metal away from said surfaces, and diverge from the straight linetravel of the metal into the forming opening or openings from which thecasting emerges. In FIGS. 1 to 4 where there are only two rolls defininga single pass, the slope is from the distal edges of the end wall towardthe central area, this being divergent to the straight line flow ofmetal into the pass, and in FIG. 5 the angularity reverses from the topto the two discharge passes near the bottom, although the slope withreference to the straight line flow is continuous, and in FIGS. 7 and 8the slope is away from the center toward the distal edges, which isopposite FIG. 4, but functionally the same. In each case the end wallhas a central area with at least two oppositelydirected portions, eachcontoured to fit about one of two rolls that provide between them acasting forming pass, and each such portion extends into the passthrough which the formed casting emerges. The faces of the end wallagainst which the molten metal is confined to retain a pool or sump ofthe molten metal between the two or more rolls, as the case may be,angle outwardly toward the roll ends toward the pass, that is, angleaway from a straight-line flow of the congealed metal on the rollsurface into the pass, the width of the pool in the direction of thelength of the rolls increasing toward the forming pass. In this mannercongealing metal is always carried away from the end wall where theedges of the end 'wall confront the roll surfaces.

I claim:

1. Casting apparatus comprising at least two confronting rolls in spacedrelation defining a molten metal holding space between them and with aforming pass through which the formed casting emerges, and an end walladjacent an end of the rolls arranged to retain molten metal in saidspace with edges contoured to conform to the surfaces of the two rollsand with a working clearance with the rolls, said end wall having thatface which contacts the molten metal being smooth and free ofirregularities and angled throughout its length with respect to the axesof the rolls in such manner that said metal-forming space increases inwidth in the direction of the length of the rolls toward the formingpass between the rolls, and means for rotating the rolls oppositely toeach other in a direction to carry metal that congeals on the surfacesthereof into the forming pass.

2. Casting apparatus comprising at least two confronting rolls in spacedrelation defining a molten metal holding space between them and with aforming pass through which the formed casting emerges, and an end walladjacent an end of the rolls arranged to retain molten metal in saidspace having portions which extend from said pass in oppositedirections, one over the surface of one roll and one over the surface ofthe other, each with edges that conform to the curvature of the rollsurface over which it extends and with which it has a working clearance,each such portion throughout its entire length being angled from thepass toward the mid transverse plane of the rollers so that they divergewith respect to a straight line flow of metal from said space into theforming pass in such manner that metal that congeals on the rollsurfaces immediately adjacent said end wall portions is carried byrotation of the rolls away from the end walls and so prevented frombecoming wedged under the end walls.

3. Casting apparatus as defined in claim 2 in which there are twohorizontal rolls in side-by-side relation, and the casting forming passis between them with the metal holding space being between the upperportions of the rolls above the forming pass, one of said end wallsbeing located adjacent each end of the two rolls, each end wall having aface portion thereof that contacts the molten metal and which is abovethat one of the two rolls about which said portion is contoured, and sodiverge from a plane passing transversely through the rolls.

4. Casting apparatus as defined in claim 2 in which there is a clusterof four rolls with their axes horizontal and with two rolls spaced abovethe other two rolls to provide a single metal holding space and twoopposite laterallyopening forming passes, there being two end plates,one adjacent each end of the rolls, each having the edges thereofcontoured to fit about and have working clearance with each of the fourrolls, the confronting faces of the two end members being smooth and areso angled with respect to the roll axes that the distance between themincreases toward said laterally-opening roll passes.

5. Casting apparatus as defined in claim 2 in which there is a clusterof four rolls arranged with their axes vertical and providing at thecenter of the cluster a molten metal holding space, the rolls of thecluster being arranged in two pairs, one pair being spaced from theother to form two opposed forming passes leading from said centralspace, the rolls of each pair being in contact with each other and beingdriven in opposite directions, there being a single end wall adjacentthe lower end of the roll cluster having the edges thereof contoured toextend around a portion of the periphery of each of the rolls with thecontoured edges of the end wall member having a working clearance withthe roll surfaces, the top face of the end wall being smooth and beingso angled with respect to a plane passing transversely through the rollsthat they diverge away from said plane in the direction of said twoforming passes in such a manner that metal congealing on the surfaces ofthe rolls forming each of the two forming passes is carried by rotationof the rolls away from said edges of the end walls toward the formingpass provided in part by that roll on which it congeals.

6. Apparatus for producing solidified metal products directly frommolten metal wherein the molten metal is introduced between rotatingrolls and solidified metal is fed out from between the rolls, thecombination comprising:

(a) a plurality of rotatable rolls mounted in adjacent and cooperatingpositions to form a metal holding sump with a casting forming passleading therefrom between the rolls,

(b) at least one confining wall for confining molten metal between itand the rolls to thereby form a sump for molten metal, the confiningwall having its edges shaped to conform to the curvation of the rollswith the edges providing a working clearance with the surface of eachroll and having the face which is toward the sump smooth and angled awayfrom a transverse plane through the rolls toward the forming pass insuch a manner that molten metal congealing on the rolls adjacent theconforming edges of the end walls is carried by rotation of the rollsaway from said edges, and

(c) means for rotating the rolls in opposite directions with thesurfaces thereof moving in a direction toward said forming pass.

7. Apparatus according to claim 6 wherein there are two rotatable rollsin side-by-side relation with their axes horizontal and a confining wallis positioned adajcent each end of the two rolls for confining moltenmetal at each end of the rolls, the distance between the end wallsincreasing in the direction of the forming pass in such a manner thatmetal congealing on the rolls is carried by rotating the rolls from thesump into the roll pass.

References Cited UNITED STATES PATENTS 2,790,216 4/1957 Hunter 164-8849,053 7/1865 Bessemer 16487 1,704,580 3/1929 Showers -253 X 1,756,1964/ 1930 Hopkins et a1. 164-87 1,903,897 4/ 1933 Harris 164-277 2,108,7532/1938 Low 164-87 2,183,010 12/1939 Coxe 164-87 3,038,219 6/1962 Hudson164-88 I. SPENCER OVERHOLZER, Primary Examiner. R. SPENCER ANNEAR,Assistant Examiner.

US. Cl. X.R. 65-253

